The present invention relates to a method of making a golf club head, more particularly to a method of welding metal parts of a club head.
In the golf club heads made up of two or more metal parts such as metal wood-type head and iron-type head, such metal parts are usually connected with each other by one side welding of butt joint, and in recent years, the use of laser welding instead of the widely employed tungsten inert gas (TIG) welding has been suggested or proposed in the Japanese patent No.2600529 and laid-open Japanese patent application JP-A-2001-293115.
On the other hand, in case of metal wood-type club heads for example, the golfers have a tendency to prefer the recent large-sized heads. Thus, the wall thickness in the welded place of such a large-sized head also has a tendency to decrease. Further, to achieve the desired performance (strength, weight and the like), the use of different metal materials is preferred. Therefore, if such metal parts are, as shown in FIG. 13(a), temporally butt jointed and a laser beam is applied to the joint part, a joint dent (g) is very liable to occur as shown in FIG. 13(b). As the wall thickness is relatively small, the joint dent (g) greatly decrease the joint strength. Further, as the wall thickness is small, if the laser beam is penetrate through the joint part, there is a possibility that the molten material trickles down towards the backside hollow, causing the shortage of the filling material. Thus, the possibility of occurrence of pinholes is also high.